I haven't tried to do any coworking in smaller cities or towns, but I guess maybe there are indie coworking spaces in places like say, Santa Rosa or Auburn.
TBH if I was designing a nomad project for myself (and wanting a significant nature/non-urban aspect to it) I think i'd do a literal van and have a real desk and chair in it. 5G internet isn't the greatest but I think it'd be easy enough, armed with a van, to seek out places within the area I want to visit with a good enough signal to make it workable.
(Obviously add rooftop solar panels and a Jackery or whatever to satisfy power needs all day.)